1662511621 has 2 divisors, whose sum is σ = 1662511622. Its totient is φ = 1662511620.

The previous prime is 1662511603. The next prime is 1662511667. The reversal of 1662511621 is 1261152661.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1655594721 + 6916900 = 40689^2 + 2630^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1662511621 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1662511321) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 831255810 + 831255811.

It is an arithmetic number, because the mean of its divisors is an integer number (831255811).

Almost surely, 2^1662511621 is an apocalyptic number.

It is an amenable number.

1662511621 is a deficient number, since it is larger than the sum of its proper divisors (1).

1662511621 is an equidigital number, since it uses as much as digits as its factorization.

1662511621 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 4320, while the sum is 31.

The square root of 1662511621 is about 40773.9085813465. The cubic root of 1662511621 is about 1184.6450113181.

The spelling of 1662511621 in words is "one billion, six hundred sixty-two million, five hundred eleven thousand, six hundred twenty-one".